[MIKEL12]

So, our EC400 from 2012 has an intermittent problem with spindle load.

We start it up in the morning and get 3-6% load on spindle starting it and letting the tool just rotate freely.
Then after a couple of hours of production the machine stops because of tool overload (i have loads set 20% over normal cutting values just to make sure nothing major happens if something breaks)
Then we run the tool freely in air again and now the load goes way up. and fluctuates on the load meter. I've seen it up as high as 43% load.
(There is no resistance in the spindle when stopping and spinning it by hand)

Leaving the machine to rest for a while solves the problem for the time being, and we get another couple of hours out of her.

Anyone have any ideas?
We have a Haas guy coming to change the Wye assembly just to check if that may be the problem.
But since the problem is there both in Y and D, i'm not exactly holding my breath.

https://youtu.be/O_RpkZvSG1Y
https://youtu.be/2nBTz8-VGG4

[Jim Dawson]

Just a guess is the windings in the spindle motor are failing. Probably time for a new motor or a rewind. But could also be the spindle drive or encoder. An oscilloscope would be useful in troubleshooting this one.

[MIKEL12]

I do have access to a oscilloscope.
What would i be looking for ?

Haas tech wants to change the vector drive as a next step, i'm reluctant about throwing spareparts on the machine and figuring out what works, it gets expensive real fast

[Jim Dawson]

If the spindle is equipped with an encoder or resolver, you would want to look at that with the scope. The test point for this might be an encoder output on the drive if it is equipped with one. The tech should be able to do this.

Exactly what you test with a scope would depend on the type of system, and what type of feedback the drive gets from the motor. To look at the output from the drive to the motor will require the proper high voltage probes. A quick phase to phase and phase to ground resistance test on the motor might tell a lot about the condition of the motor. The tech should also be able to do this.

[HFO Tech]

A new spindle encoder,belt, and pulleys should resolve this issue.

[MIKEL12]

Wye contactor seems to have been the problem, we have been running without any problems for a couple of weeks now.

[haastec]

Wye contactor seems to have been the problem, we have been running without any problems for a couple of weeks now.

Thanks for the follow up and happy to hear you have the problem solved.

[Andriy77]

We have higher spindle load on HAAS ST-20, 10-12% at 1000 rpm, 20-22 % at 2500 rpm. I have checked belt, tension, encoder belt, it's OK. Where is noise from the spindle motor pulley, it seems bearing of motor. Can motor bearing affect on load monitor? Machine worked 3000 hours only.

[MIKEL12]

We have higher spindle load on HAAS ST-20, 10-12% at 1000 rpm, 20-22 % at 2500 rpm. I have checked belt, tension, encoder belt, it's OK. Where is noise from the spindle motor pulley, it seems bearing of motor. Can motor bearing affect on load monitor? Machine worked 3000 hours only.

I'm guessing the motor would get hot if the bearing is faulty since it would be creating heat alongside the motor and running load of 20%
You should make a post over in haas lathe forum instead, this is the wrong place for this question

You could try this:
https://www.youtube.com/watch?v=wRt_ehXBjDw

I only have inline spindles on our lathes, but here i would try to run the spindle at some rpm and hit the emergency stop.
If the spindle stops quicker than usual something is braking and making friction.